Angular Velocity Calculator
Rotation rate in rad/s, rpm and deg/s, plus rim speed at a radius.
The chain of conversions
ω = Δθ / Δt v = ω × r
One full turn is 2π radians, so a revolution every half second is 12.57 rad/s, which is 120 rpm. Multiply by the radius for the speed of a point on the rim: the same rpm moves a point twice as fast at twice the radius, which is why blade tips do the cutting.
Angular acceleration
The same pattern one level up: α = Δω / Δt, in rad/s². Spin-up times of hard drives, flywheels and washing machine drums all come from it, paired with torque through T = Iα, the rotational twin of F = ma.